Detachable, adjustable machine knife



Sept. 15, 1964 w. c. THYNG 3,148,575

DETACHABLE, ADJUSTABLE MACHINE KNIFE Filed Aug. 7, 1958 nnnn DU INVENToR. MLTE'R C. T11 YN G' Pme/n v 'PJM AT TORNEYS' States Patent 3,148,575 DETACHABLE, ADJUSTABLE MACHINE KNIFE Walter C.. Thyng, Methuen, Mass., assignor to John W. Bolton di Sons, Inc., Lawrence, Mass., a corporation of Massachusetts Filed Aug. 7, 1958, Ser. No. 753,843 2 Claims. (Cl. 83-700) This invention relates to detachable machine knives such as are used in paper cutting machines.

In paper cutting machines there has usually been a knife bar which is an integral part of the machine and has been variously described as a cutter bar, a knife holder, a blade carrier or a knife plate.

The machine knife has usually been detachably axed to the knife bar by bolts or screws and such knives have been variously described as the cutter, the blade, the cutter blade or the knife.

Because the cutting edge of the machine knife wears down and must be periodically sharpened, there have been many proposals for slidably adjusting the knife relative to the knife bar and providing shims or thrust screws for adjusting the seating of the knife in the knife bar recess. It should be noted, however, that the detaching, sharpening, attaching and adjusting of a machine knife of considerable weight and length is a diiiicult task and that the manpower exerted is all for the purpose of sharpening and adjusting only the beveled cutting edge of the knife.

It has heretofore been proposed, for example, in U.S. Patent 2,178,710 to Valiquette, of November 7, 1939, to provide a detachable cutting strip along the beveled edge of a cutter blade whereby the strip only need be removed, sharpened, adjusted or replaced. The cutting strip is placed on the beveled front face of the cutter so that it will be pushed into closer engagement with the body of the knife bar rather than away from such engagement.

The principal object of this invention is to provide a machine knife with a thin, elongated, relatively high, or wide, cutting insert of hard steel in a thin, elongated, relatively high, or wide, recess in the rear face thereof, the insert having a beveled lower edge and the insert being slidably adjustable and detachable without danger of breakage.

Another object of the invention is to provide a machine knife of the usual configuration adapted to lit on the usual knife bar but having a relatively thin, high, hard steel cutting insert nearly as high as the knife, to permit multiple sharpening and extension of the cutting edge before the strip becomes unusable.

A further object of the invention is to provide a machine knife in the form of a soft metal adapter and a hard metal insert, the insert being nearly as long and as high as an ordinary knife but considerably less thick and being fixed to the adapter by an upper and a lower row of fastening screws with the lower row well down toward the cutting edge to counteract leverage during the cutting operation.

Other objects and advantages of the invention will be apparent from the claims, the description of the drawing and from the drawing in which FlG. l is an end view in section on line 1-1 of FIG. 2 of a machine knife constructed in accordancel with the invention.

FIG. 2 is a View similar to FIG. 1 showing the hard metal insert slidably extended to compensate for wear.

FIGS. 3 and 4 are views similar to FIGS. l and 2 of a modified form of the invention.

FIG. 5 is a fragmentary, front view of the device shown in FIG. l and FIG. 6 is a fragmentary front View of the device shown in FIG. 3.

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In the drawings, 20 is the knife bar of a cutting machine and it is an integral part of the machine which reciprocates vertically while supporting a machine knife. Knife bar 20 usually includes a line of spaced holes such as Z1, for receiving the fastening bolts 22 which detachably secure the machine knife.

The machine knife 23 of this invention is thin, elongated and relatively high, or wide and includes the adapter 24, of soft metal, and the insert 25, of hard metal, such as high carbon tool steel. The generally rectangular cross section and the original, at, thin, high, configuration or outline of the knife 23 is maintained as the cutting edge wears down, by slidably extending the insert to compensate for wear on the cutting edge after sharpening. Although the knife 23 is itself capable of extension of its cutting edge it may be handled in the same manner as an ordinary machine knife and may be mounted on knife bar 2t) for slidable adjustment of wear in accordance with various connections well known in the prior art. When used on a cutting machine having no such adjustment system, the knife 23 provides the same while reducing the weight of metal which must be removed from the machine for sharpening purposes.

The adapter 24 includes an upper portion 26, an intermediate portion 27 and a lower portion 2S as well as a flat front face 29 and a parallel, fiat rear face 30. The top edge 33 of adapter 24 is firmly seated in the usual recess 34 of knife bar 20 and the full thickness upper portion 26 of the adapter includes a longitudinally extending row of spaced, threaded holes such as 35 for the attachment bolts or screws 22. A beveled lower edge 36 is preferably provided on the lower portion 28 of adapter 24 and a plurality of longitudinally spaced screw receiving apertures, such as the slot 37, are provided in the front face 29. Each slot 37 extends from the lower portion 2S, proximate the beveled face 36 upwardly along the intermediate portion 27 of adapter 24 to the upper portion 26. Shoulders such as at 38 are provided in each slot 37 in order that the heads 39 of the clamping screws 40 and 41 may be within the confines of the knife while serving their clamping purpose. Adapter 24 includes a recess 44, of generally rectangular cross section in the rear face 30 thereof which extends the full length of the intermediate and lower portions 27 and 28 for receiving the insert 25.

The insert 25 is of the same cross sectional Outline as the rabbet or recess 44 in the adapter 24, except for the cutting edge 45 and is formed by a relatively thin strip of tool steel coextensive in length with adapter 24 and nearly equal in height thereto. It will be understood that since the front, beveled cutting edge 45, of insert 25, wears down and must be repeatedly sharpened, the height dimension of the insert permits long life and many extensions While offering suiiicient area of contact with adapter 24 to insure a firm anchor thereto. Insert 25 includes an upper portion 46 having a top edge 47, which is originally firmly seated on the corresponding face 48 of the recess 44, and includes an intermediate portion 49 as well as a lower portion 50. The flat rear face 53 of insert 25 is coplanar with the rear face 3l) of adapter 24 and overlaps the same along a central, vertical, longitudinal centre line of knife 23 and the dat front -face 54 is slidable on the corresponding face 55 of recess 44.

A plurality of rows 56, of spaced threaded screw holes such as 57, 58, 59, 60 and 61 are provided in the front face 54 of insert 25, each row being opposite and substantially coextensive with one of the shouldered slots 37.

As shown in FIGS. l, 2 and 5 the detachable clamping means 63 of the machine knife 23 includes at least an upper line 64 and a lower line 65 of clamping screws such as 4t] and 41, the screws being threaded in the screw receiving holes of the insert. It should be noted that the lower line 65 is well down into the lower portion 28 of adapter 24, proximate the beveled lower edge 36 and therefore tends to reduce the leverage effect of the cutting pressure against the beveled cutting edge 45 of insert 25. As the cutting edge 45 wears down the clamping screws can be removed and replaced in the holes 57, 58, 59, 60, 61 and 62 to clamp the slidable insert 25 in progressively extended positions relative to adapter 24, thereby maintaining the original, flat, thin relatively high, or wide configuration of the knife and the original clearance 66 between beveled face 36 and beveled cutting edge 45. As shown in FIG. 1 the distance between the holes 57 and 58 is about the same as the initial clearance 66 and extension of insert is usually accomplished when the clearance 66 becomes eliminated by wear.

Adjustable insert seating means 67 is provided in the form of a plurality of spacers such as 68, of progressively larger size and fitting in recess 44 between the top face 47 of insert 25 and the face 48 of the recess. Each spacer such as 68 includes a plurality of fastening screws such as 69 which may be threadedly attached to the insert, for holding the spacer in place, when the insert is removed for sharpening (FIG. 2).

A modification is shown in FIGS. 3, 4 and 6 wherein the clamping means includes a plurality of dovetail grooves such as at 70 longitudinally spaced along the upper and intermediate portions of the insert 71, an upper line of holes such as 72 and a lower line of holes such as 73 in the adapter 74. An anchor slide, or block,

75 is slidable in each groove 78 and provided with threaded holes such as 77 and 78 for the fastening screws 79 and 80. The tightening of screws 79 and 8) thus clamps the insert at any desired slidable position within the recess 81 of the adapter 74. The adjustable seat means 83 comprises a line of spaced thrust screws, such as 84, each seated in the upper portion 85 of the adapter 74 and each having a knurled head 86 in the recess 91 accessible from the front face 87 of the modified knife 88. The top face 89 of the insert 71 is in axial engagement with the set screws 84 and by turning the set screws the insert seat is adjusted to conform with wear on the cutting edge 90. The knurled head 86 is internally threaded on the exterior threads of set screw 84 and a locking set screw 92 is provided for fixing the same in place after adjustment.

As shown in the drawing the flat, front face 29 of adapter 24 and the fiat rear face 53 of insert 25 are uniformly spaced apart, and parallel, at all times for maintaining the thin, elongated, relatively high, or wide, configuration of the machine knife 23 of the invention. The insert 25 and the insert recess 44 of adapter 24 are both more than half as high, or wide, as the knife 23 itself. The adapter 24 and the insert 25 are substantially equal in height, or width, to provide maximum slidable overlap.

I claim:

1. A thin, elongated machine knife of predetermined height adapted to be mounted on a knife bar of a cutting machine, said knife comprising an adapter having an upper portion of full knife thickness with spaced attachment holes therealong, a full height, fiat (front face on said adapter forming the front face of said knife and a at rear face on said adapter with a rabbet recess along the intermediate and lower portions thereof; a cutting insert of tool steel having its upper and intermediate portions overlapping said adapter within said rabbet recess and in slidable engagement with the intermediate and lower portions of said adapter, a lower portion of said insert projecting beyond said adapter and terminating in a beveled cutting edge and a fiat rear face on said insert parallel to, and uniformly spaced from the front face of said adapter; said adapter and insert being substantially equal in height and substantially equal in thickness in the overlapping portions thereof; a plurality of knurled set screws mounted to turn on an axis parallel to the rear face of said insert in the upper portion of said adapter the lower terminal tip of each said set screw engaging the upper edge of said insert; a plurality of anchor blocks each slidable in vertical dovetail grooves in the upper and intermediate portions of said insert and a plurality of fastening screws mounted in the intermediate and lower portions of said adapter and threaded in holes in one of said anchor blocks for clamping said insert in the rabbet recess of said adapter.

2. A machine knife having the outline of a thin blade of generally rectangular cross section with parallel front and rear faces, said knife comprising an adapter, of relatively soft metal, having a fiat, front face forming the said front face of said knife, having an upper portion of full knife thickness with spaced holes therealong for detachable mounting on the knife bar of a cutting machine and having an intermediate portion and a lower portion of reduced knife thickness forming an insert receiving recess of rectangular cross section in the rear face thereof; an insert, of relatively hard metal, having a fiat rear face parallel to, and uniformly spaced from the front face of said adapter and forming the said rear face of said knife; having an upper portion of rectangular cross sectional outline equal in thickness to the depth of said recess and slidably mounted therein in overlapping relation with the said intermediate and lower portions of said adapter and having a lower portion with a beveled cutting edge in the lower face thereof, said edge projecting beyond said adapter; means for detachably clamping said insert within said recess comprising a plurality of dovetail grooves longitudinally spaced along the upper and intermediate portions of said insert, an anchor block slidable in each said groove and having a pair of spaced, headed, set screws threaded therein and a pair of set screw apertures in said adapter, opposite each said groove, for receiving the heads of said set screws; and means for adjustably seating said insert within said recess, both of said means permitting slidable extension of said insert relative to said adapter, when said cutting edge is worn, to restore the original outline of said knife.

References Cited in the tile of this patent UNITED STATES PATENTS 

1. A THIN, ELONGATED MACHINE KNIFE OF PREDETERMINED HEIGHT ADAPTED TO BE MOUNTED ON A KNIFE BAR OF A CUTTING MACHINE, SAID KNIFE COMPRISING AN ADAPTER HAVING AN UPPER PORTION OF FULL KNIFE THICKNESS WITH SPACED ATTACHMENT HOLES THEREALONG, A FULL HEIGHT, FLAT (FRONT FACE ON SAID ADAPTER FORMING THE FRONT FACE OF SAID KNIFE AND A FLAT REAR FACE ON SAID ADAPTER WITH A RABBET RECESS ALONG THE INTERMEDIATE AND LOWER PORTIONS THEREOF; A CUTTING INSERT OF TOOL STEEL HAVING ITS UPPER AND INTERMEDIATE PORTIONS OVERLAPPING SAID ADAPTER WITHIN SAID RABBET RECESS AND IN SLIDABLE ENGAGEMENT WITH THE INTERMEDIATE AND LOWER PORTIONS OF SAID ADAPTER, A LOWER PORTION OF SAID INSERT PROJECTING BEYOND SAID ADAPTER AND TERMINATING IN A BEVELED CUTTING EDGE AND A FLAT REAR FACE ON SAID INSERT PARALLEL TO, AND UNIFORMLY SPACED FROM THE FRONT FACE OF SAID ADAPTER; SAID ADAPTER AND INSERT BEING SUBSTANTIALLY EQUAL IN HEIGHT AND SUBSTANTIALLY EQUAL IN THICKNESS IN THE OVERLAPPING PORTIONS THEREOF; A PLURALITY OF KNURLED SET SCREWS MOUNTED TO TURN ON AN AXIS PARALLEL TO THE REAR FACE OF SAID INSERT IN THE UPPER PORTION OF SAID ADAPTER THE LOWER TERMINAL TIP OF EACH SAID SET SCREW ENGAGING THE UPPER EDGE OF SAID INSERT; A PLURALITY OF ANCHOR BLOCKS EACH SLIDABLE IN VERTICAL DOVETAIL GROOVES IN THE UPPER AND INTERMEDIATE PORTIONS OF SAID INSERT AND A PLURALITY OF FASTENING SCREWS MOUNTED IN THE INTERMEDIATE AND LOWER PORTIONS OF SAID ADAPTER AND THREADED IN HOLES IN ONE OF SAID ANCHOR BLOCKS FOR CLAMPING SAID INSERT IN THE RABBET RECESS OF SAID ADAPTER. 